The present invention relates to a ball valve having replaceable seals which may be repaired or replaced while the valve remains in use. It is known from my earlier U.S. Pat. No. 4,512,360 to provide a ball valve with replaceable seals which can be repaired or replaced without removing the valve from the line.
The present invention is directed to various improvements in a ball valve and in particular directed to providing a seat ring having seals which can more easily be replaced and repaired. In the present valve the seals can be replaced while the valve remains in service under pressure. This is an important advantage over ball valves that require the ball valve element to be removed in order to change the seals.